<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>正则作业</title>
    <style>
      form {
        width: 400px;
        border: 10px solid pink;
        padding: 20px;
      }

      label {
        display: block;
        height: 80px;
        position: relative;
      }

      input {
        height: 30px;
        font-size: 20px;
        padding-left: 20px;
      }

      label > span {
        position: absolute;
        left: 0;
        top: 35px;
        font-size: 20px;
        color: red;
        display: none;
      }
    </style>
  </head>
  <body>
    <form>
      <label>
        用户名: <input class="username" type="text" />
        <!-- 数字字母开头6～12位 忽略大小写 -->
        <span>请按照规则填写用户名</span>
      </label>
      <label>
        密码: <input class="password" type="text" />
        <!-- 数字字母下划线 6～12位 -->
        <span>请按照规则填写密码</span>
      </label>
      <label>
        手机号: <input class="phone" type="text" />
        <!-- 11位数字即可 -->
        <span>请按照规则填写手机号</span>
      </label>
      <label>
        <!-- 6～12位 开头为数字大小写字母 中间为数字字母下划线均可-->
        <!-- @ 只接收qq 163 sina -->
        <!-- com或者cn -->
        邮箱: <input class="email" type="text" />
        <span>请按照规则填写邮箱</span>
      </label>
      <input type="button" value="完善资料" />
    </form>
    <script>
      //用户名
      let name = document.querySelector('.username')
      function Name(){
        console.log(name);
        let spans = document.querySelectorAll('span')
      let regName = /^[0-9a-z]\w{5,11}$/i
      if(regName.test(name.value)){
        spans[0].style.display=""
      }else{
        spans[0].style.display="block"
      }
      }
      name.oninput = function(){
        Name()
      }

      //密码
      let pwd = document.querySelector('.password')
      function Pwd(){
        let spans = document.querySelectorAll('span')
        let regPwd = /^\w{6,12}$/
        if(regPwd.test(pwd.value)){
          spans[1].style.display=''
        }else{
          spans[1].style.display='block'
        }
      }
      pwd.oninput = function(){
        Pwd()
      }

      //手机号
      let phone = document.querySelector('.phone')
      function Phone(){
        let spans = document.querySelectorAll('span')
        let regPhone = /^\d{11}$/
        if(regPhone.test(phone.value)){
          spans[2].style.display=''
        }else{
          spans[2].style.display='block'
        }
      }
      phone.oninput = function(){
        Phone()
      }

      //邮箱
      let email = document.querySelector('.email')
      function Email(){
        let spans = document.querySelectorAll('span')
        let regEmail = /^[0-9a-z]\w{5,11}@(qq|163|sina)\.(com|cn)$/
        if(regEmail.test(email.value)){
          spans[3].style.display=''
        }else{
          spans[3].style.display='block'
        }
      }
      email.oninput = function(){
        Email()
      }
    </script>
  </body>
</html>
